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swiotlb: Enforce page alignment in swiotlb_alloc()

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commit 823353b7cf0ea9dfb09f5181d5fb2825d727200b upstream.

When allocating pages from a restricted DMA pool in swiotlb_alloc(),
the buffer address is blindly converted to a 'struct page *' that is
returned to the caller. In the unlikely event of an allocation bug,
page-unaligned addresses are not detected and slots can silently be
double-allocated.

Add a simple check of the buffer alignment in swiotlb_alloc() to make
debugging a little easier if something has gone wonky.

Cc: stable@vger.kernel.org # v6.6+
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Petr Tesarik <petr.tesarik1@huawei-partners.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Will Deacon 2024-06-17 11:23:13 -03:00 committed by Greg Kroah-Hartman
parent 9f2050106f
commit 6033fc9522
1 changed files with 6 additions and 0 deletions
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6
kernel/dma/swiotlb.c
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@ -1627,6 +1627,12 @@ struct page *swiotlb_alloc(struct device *dev, size_t size)
return NULL;
tlb_addr = slot_addr(pool->start, index);
if (unlikely(!PAGE_ALIGNED(tlb_addr))) {
dev_WARN_ONCE(dev, 1, "Cannot allocate pages from non page-aligned swiotlb addr 0x%pa.\n",
&tlb_addr);
swiotlb_release_slots(dev, tlb_addr);
return NULL;
}
return pfn_to_page(PFN_DOWN(tlb_addr));
}